It is known to package heat generating electrical components such as power ICs in single inline packages (SIPs) aligned in groups with leads soldered to a circuit board. Each SIP is a flat package with one major heat sink surface, such as a copper face, designed for heat dissipation by transfer to a heat sink. Various schemes were introduced to couple the SIPs to heat sinks.
In the interest of minimizing the circuit board space required for each SIP, it has been proposed to place the SIPs at an angle to the circuit board in two adjacent rows supported on a carrier between the rows for securely maintaining the position of each SIP with the heat sink surface facing outward, and a case enclosing the components and having internal surfaces tightly engaging the heat sink surfaces for efficient thermal transfer. FIG. 1 is an example of this configuration. There a circuit board 10 supports a carrier 12 which has inclined sides 14 at a predefined angle to one another, and a ledge 16 near the bottom of each side adjacent the circuit board. A row of SIPs 18 is seated on each ledge 16 with a surface 20 flush against an inclined side 14, and component leads 22 extend through holes in the circuit board 10. Heat sink surfaces 24 opposite the surfaces 20 face outward and a thermally conductive case 26 bears against the heat sink surfaces 24 for heat removal. For that purpose the case 26 includes opposing surfaces 28 having the same included predefined angle as the carrier sides 14 so as to bear flush against the heat sink surfaces 24 when the SIPs 18 are seated on the carrier. The case 26 extends across the circuit board 10 and other parts of the case, not shown, may similarly couple to other SIP and carrier assemblies on the same circuit board.
Several varieties of structures akin to that of FIG. 1 and using the same principles may be designed. A different carrier 12' is shown in FIG. 2 by way of example. For clarity, only one SIP 18 is shown installed on the carrier 12'. While FIG. 1 suggests that the sides 14 may be flat surfaces, the carrier 12' includes pairs of spaced ribs 32 instead of flat surfaces to define inclined planes and support the SIPs at the correct angle. A short ledge 16' is provided for each SIP. The space between the ribs 32 of each pair and beneath the SIP may contain a spring, not shown, for urging the SIP toward the case when assembled.
The manufacture of the assemblies requires that the SIPs be arranged on the carrier and the leads inserted through holes in the circuit board, soldering the leads to the board, and installing the case. It is important that before soldering, the components be properly seated on the ledges and the inclined sides; if the placement is not correct, the case will not contact the SIPs for good heat transfer, and the assembly is likely to fail either in testing or in use.